Break can affect momentum if it is too long but when people serve all year round without breaks, it leads to burn out. Pattern your small group system around the semester system. Many people are used to it already. Give them minimum 2 weeks break and then they resume leading small groups again
The mistake I made in my first year was the small group leaders were serving all year round. By October ending, they were burning out and you could see lethargy was setting in the work they initially loved to do.
People are already used to semesters or seasons so have breaks and create semesters out of your care system.
You can have a Spring semester from February to April, Summer semester from June to August and Fall Semester from October to December. These give them January, May and September to relax.
Then Jesus said, “Let’s go off by ourselves to a quiet place and rest awhile.” He said this because there were so many people coming and going that Jesus and his apostles didn’t even have time to eat.
Mark 6:31
Give your leaders and volunteers intermittent rest especially if you operate a lay ministry system like our church does. Those bi-weekly to monthly breaks keep them fresh all year round.